Hi Wolfgang,
On Tuesday 06 March 2012 08:10 PM, Wolfgang Denk wrote:
Dear Prabhakar Kushwaha,
In message1329296042-28506-1-git-send-email-prabhakar@freescale.com you wrote:
Debugger's ability to debug an application is constrained by the architecture's debug IP / run-control solution that may impose certain requirements for the application itself. Similarly, when referring to the e500 and e500v2 architecture, there are two basic rules any application has to respect in order to allow full debugging support: 1. Keep MSR[DE] bit set 2. Have a valid opcode that can be fetched from the debug exception vector [IVPR|IVOR15]. Here MSR = Machine State register
This patch makes sure of point "1" and make MSR[DE] bit is set uniformaly across the different execution in address space.
Does it make sense to repeast the whole README here?
I agree. it should not be. But as i sent a series of patch, this change require some explanation.
I will change the description.
diff --git a/arch/powerpc/cpu/mpc85xx/start.S b/arch/powerpc/cpu/mpc85xx/start.S index 7bfa2d5..09111e6 100644 --- a/arch/powerpc/cpu/mpc85xx/start.S +++ b/arch/powerpc/cpu/mpc85xx/start.S @@ -82,6 +82,11 @@ .globl _start_e500
_start_e500: +#if defined(CONFIG_E500_V1_V2) +/* Enable debug exception */
- li r1,MSR_DE
- mtmsr r1
+#endif
Why is this #ifdef needed here?
This #ifdef is to make sure MSR_DE bit is set before u-boot's actual code start executing. it is for overcoming one of the requirement of debugging i.e. Keep MSR_DE bit set.
#if defined(CONFIG_SECURE_BOOT)&& defined(CONFIG_E500MC) /* ISBC uses L2 as stack. @@ -729,8 +734,8 @@ create_init_ram_area: msync tlbwe
- lis r6,MSR_IS|MSR_DS@h
- ori r6,r6,MSR_IS|MSR_DS@l
- lis r6,MSR_IS|MSR_DS|MSR_DE@h
- ori r6,r6,MSR_IS|MSR_DS|MSR_DE@l
And why don;t we need such an #ifdef here?
I found similar piece of code in start.S without any #define at label _start_cont. That's why i made it like this.
if required i will put it under #define.
Also, CONFIG_E500_V1_V2 is undocumented.
Definition of this #define is part of documentation. I will add comment before using it.
--Prabhakar